As CEO of Microsoft, Steve Ballmer was famous for over-the-top enthusiasm. Now he’s brought that same passion to the N.B.A. — and to a pet project called USAFacts, which performs a sort of fiscal colonoscopy on the American government.

Eric Garcetti, the mayor of Los Angeles, has big ambitions but knows he must first master the small stuff. He’s also a polymath who relies heavily on data and new technologies. Could this be what modern politics is supposed to look like?

Our Self-Improvement Month concludes with a man whose entire life and career are one big pile of self-improvement. Nutrition? Check. Bizarre physical activities? Check. Working less and earning more? Check. Tim Ferriss, creator of the Four-Hour universe, may at first glance look like a charlatan, but it seems more likely that he’s a wizard -- and the kind of self-improvement ally we all want on our side.

Our latest Freakonomics Radio episode is called “The President of Harvard Will See You Now.” (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.) It features an in-depth interview with Drew Gilpin Faust, and explores how a (self-described) "pain-in-the-neck" little girl from rural Virginia came to run the most powerful university in the world.

Our latest Freakonomics Radio episode is "Aziz Ansari Needs Another Toothbrush," in which the comedian, actor -- and now, author -- answers our FREAK-quently Asked Questions. (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

Aziz Ansari is best known for playing Tom Haverford on Parks and Recreation, the NBC sitcom starring Amy Poehler. The show was never a huge hit, but it was beloved -- In part because it was smart but also because (IMHO) the show was, at its core, sweet. Although Ansari's Haverford was perhaps the most selfish and hustle-y character on the show – and yet he too was pretty sweet, deep down.

Our latest Freakonomics Radio episode is called “Nate Silver Says: 'Everyone Is Kind of Weird" (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

Since its inception in 1944, the World Bank, a multilateral organization charged with financing the development of poor nations, has been led by macroeconomists, bankers, and government insiders. The White House’s 2012 nomination of President Jim Yong Kim -- a physician, anthropologist, and academic who used to advocate dismantling the Bank -- broke the mold. He is the focus of our latest Freakonomics Radio podcast, "Hacking the World Bank." (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

In less than three years, Kim has overhauled the Bank and laid out ambitious goals -- including a 2030 deadline to rescue the more than 1 billion people who live in extreme poverty. Kim is also -- along with the Bank’s chief economist Kaushik Basu -- eager to apply the insights of behavioral economics to development policy. That is the focus of Kim's conversation today with Stephen Dubner.